‘John Barleycorn’, that most English of songs, sets the tone nicely. Seeing Martin Carthy in full flight, possibly at the same age the old-timers were when the stripling Carthy saw them (Sam Larner in ’58 at the Ballad and Blues Club was a life-changing moment, apparently), is both poignant and strangely heartening. With luck, dedication and long life, we might all become old-timers, just like our first idols. But whereas the original country singers seldom bothered with instrumental virtuosity and were content just to put the song across, Carthy has it all, as an enthralling storyteller with a distinctive, forceful guitar style.

He’s also, undoubtedly, travelled further and performed more widely than Sam Larner, Walter Pardon et al. He’s as comfortable with an audience as you or I would be in a pub with some dear old friends, and his conversation is compelling. What did I learn? For one thing, Carthy got ‘Scarborough Fair’ from The Singing Island, a songbook compiled by Ewan MacColl and Peggy Seeger, and MacColl got it from Mark Anderson, a retired miner, in Yorkshire in 1947. Thus, with typical self-effacement, Carthy undermines his major claim to fame in pop culture (the unspoken message: yes, he taught ‘Scarborough Fair’ to Paul Simon, but he only had it from a book). This comes in the introduction to ‘The Bonny Moor Hen’, another song with an Anderson source. It’s characteristic of Carthy to sidestep the obvious too.

With such a vast repertoire, Carthy can chase threads and follow the inspiration of the moment in structuring a set. A poacher theme begins to emerge, as ‘The Bonny Moor Hen’ is succeeded by ‘The Bold Poachers’, which escalates to a wider sense of injustice - ‘My Son John’ is an odd mix of heartlessness and indignation, but powerfully conveys its anti-war message - to be dispelled by this indisputable bit of advice from the Music Hall song that follows: “Don’t go in the lions’ cage tonight, mother.”

A swift change of guitar, and a less swift tune-up, and Carthy confides that he was electrified when he read the first four and a half verses of the next song. This turns out to be ‘The Famous Flower of Serving Men’, one of those big ballads that Carthy specialises in, and a transforming song in every sense. It may be that the English folk canon rebounds in instances of cross-dressing, infanticide, magic realism, courtly intrigue and bloody revenge - but all in one song!?

And note the strange stretching of time. The original atrocity is conveyed with the terseness and dispassion of an account by a shocked survivor. (“My mother did me deadly spite, for she sent thieves in the dark of the night…”) whereas retribution, when it comes, is lingered over and savoured in every detail (“the fire took first all on her cheek…”).

Why only the first “four and a half verses”? Could it be that ‘The Famous Flower of Serving Men’, in its definitive form, is largely the product of Martin Carthy’s craft? The notes on the inner of Carthy’s LP, Shearwater, are informative. If I understand right, Carthy bypasses the Broadside version and expands on a short text by Sir Walter Scott, and sets to a tune learnt from Hedy West. And the riff, surely, is Carthy’s own invention. Forget ‘Scarborough Fair’: ‘The Famous Flower of Serving Men’ is Carthy’s towering achievement.

Another running theme, implied rather than declared, is the undeniable blessing of possessing a strong wife. This was the sub-text of ‘The Lochmaben Harper’ and also, in a more backhanded way, ‘The Devil and the Feathery Wife’. Of course, amateur psychology can only get you so far. Let’s not make too much of the fact than an alternative title for another song (performed on his recent tour with Eliza) is ‘The Daughter in the Dungeon’).

A word too for Carthy’s highly individual guitar style, with its surging rhythm and syncopated accents, often following the melody line like a second voice. ‘The Third Man Theme’ was a happy choice of encore, bringing black and white film into Carthy’s revivalist remit: as if digesting and embodying the best of all previous folk music was not enough!